The present invention generally relates to a unit which exhausts air from the crawl space area of a dwelling or other building with a space below the sub-floor, and more particularly, relates to a ventilator with an improved installing and mounting means which is low voltage, thus having the ability to be wired through standard irrigation timers.
Many structures are built with underlying air space under the sub-floor, which for the sake of convenience, will be called crawl space for the purpose of this application. These crawl space areas can accumulate substantial amounts of moisture due to poor drainage of the soil, environmental factors such as rainfall and humidity, and even landscape irrigation. This excessive moisture, causes humidity to build and provides a breeding ground for mold, mildew and biological contaminants which are known to cause asthma as well as other severe allergic health problems. In fact, the Consumer Federation of America calls our sick houses the xe2x80x9cnumber one health and safety issue of our timexe2x80x9d adding billions of dollars annually to the nation""s health bill. Contaminants under the subfloor build, and eventually permeate into the dwelling itself, causing air pollution inside. This indoor pollution is believed responsible for the huge increase in hospitalizations for Asthmaxe2x80x94an increase of 50% for adults and 200% for children in the past 20 years. Not only does excessive moisture in crawl space areas under buildings lead to health problems, it also promotes rot and decay in the wood substructure and rust to any metal members, such as jackstands, support brackets, etc., costing billions in water damage repairs annually. Also, many naturally occurring gases and odors can occur under these buildings, and without the aid of a ventilator to allow them to escape, they can build to dangerous levels. Among the most dangerous of these gases is Radon, which is considered to be the most serious cancer causing agent in the environment. In combination, these contaminates can have synergistic effects, compounding the health risks further.
In many of these structures, particularly more recently built dwellings, there is a very low rate of air exchange between the air in the crawl space and the air outside the dwelling. This is due in part to recent trends towards high energy efficient construction. These practices involve the use of insulations to make the dwelling more tightly sealed, and sealing cracks and other air leaks to prevent heated or cooled air from escaping, and outside air which requires heating or cooling from randomly entering at an excessive rate. In effect, such houses and buildings become, to various degrees, closed systems. The result of an insufficient inlet fresh air volume flow rate into, and out of, such tight enclosed spaces is that contaminants accumulate inside to health affecting levels. To emphasize this point, it is estimated by some health care researchers that presently two persons per hour, in the United States alone, contract lung cancer as a result of contact with Radon in poorly ventilated houses and other buildings.
Most buildings with crawl space areas rely on passive air to circulate the air from inside the enclosed space under the sub-floor to the outside environment through openings in the foundation walls. Passive systems rely on environmental conditions, such as the wind, which is neither constant nor provides important exhaust air flow.
To deal with this problem, a number of ventilators have been created to assist in exhausting the air from the crawl space area through various methods. A search of existing Patents shows that numerous inventors have realized the need for a method to provide inlet fresh air to crawl space areas under dwellings and have proposed various systems, and methods of their use.
Many of these ventilator units, either the unit itself or it""s housing, must be mortared in place in the foundation wall at the time it is constructed, and are therefore not suited for installation in a pre-existing situation, such as in existing constructions. Some of the ventilators are permanent installations, either the unit itself or its housing, and once installed, cannot be removed without the assistance of a person skilled in masonry techniques. Many of the ventilators require access underneath the sub-floor for installation. This requires a person the difficult and time consuming task of maneuvering in a crawl space area for the purpose of installing the ventilator, increasing the need for a professional. Other ventilators require permanent or xe2x80x9chardxe2x80x9d wiring, requiring the skills of a professional electrician, further increasing the cost of installation.
Many of the ventilators in the prior art function on passive air flow and have no means for exhausting the air actively. These passive ventilators are designed with either a simple screen or a system of louvers that open and close to let air pass through. A number of ventilators were found to utilize either temperature sensing devices or humidity sensing devices, or both, causing an increase in manufacturing costs as well as creating a higher chance of unit malfunction due to the complexity of these devices. A few of the ventilators with a louver system were controlled to open and closed either with a solenoid or bi-metallic element, or temperature sensitive compression spring.
Following is a brief description of the prior art found in the patent search. There are ventilators that rely on a passive system to move air through as discussed above. These include U.S. Pat. No. 4,699,045 to Robert C. Hensley, Oct. 13, 1987 in which he discloses a thermostatically actuated ventilator with adjustable louvers and separate support frame that is to be frictionally mounted in an opening of a foundation wall.
Another passive system is that of U.S. Pat. No. 4,821,628 to Paul M. Sarazan Jr. and Dennis A. Beam Jr., Apr. 18, 1989 which discloses a shallow profile foundation ventilator consisting of a decorative molded frame with screening for mounting within an opening in a foundation wall, which is mostly intended for aesthetic purposes.
Another passive ventilator system discovered in the prior art is U.S. Pat. No. 4,274,330 to Alfred E. Witten and Howard W. Green, Jun. 23, 1981 in which is disclosed a ventilator with a separate mounting frame which said ventilator slides therein. This ventilator is also decorative, and mainly for appearances only.
A passive ventilator that must be permanently installed with mortar in a foundation wall during construction is disclosed in U.S. Pat. No. 5,460,572 to Arthur L. Waltz and David A. waltz, Oct. 24, 1995.
Disclosed in U.S. Pat. No. 4,493,456 to Paul M. Sarazan and Dennis A. Beam, Jan. 15, 1985, is another passive ventilator that includes a system of inter-connected louvers that open and close in response to a thermally responsive spring.
U.S. Pat. No. 4,175,480 to Dennis A. Beam Jr. and Paul M. Sarazan Jr., Nov. 27, 1979 discloses a passive ventilator with adjustable louvers with a support frame that connects to an opening in masonry walls.
In yet another invention, U.S. Pat. No. 4,290,554 to Robert C. Hensley, Sep. 22, 1981 discloses a temperature actuated foundation ventilator that also has a system of louvers controlled by a bimetallic element that responds to changes in temperature to move a control link that extends into the housing, into pivotal engagement to open and close said louvers. This ventilator is permanently installed with mortar into the foundation opening.
U.S. Pat. No. 4,587,892 to Alvin E. Witten and Erik H. Witten, May 13, 1986 discloses a passive ventilator in which it utilizes a compression spring to frictionally mount within a crawl space opening in order to keep the mounting frame secure as it contracts and expands in response to changes in temperature. It includes a shutter system that opens and closes in response to temperature changes.
A more simple passive design is that of U.S. Pat. No. 4,711,160 to Alvin A. Witten and Erik H. Witten, Dec. 8, 1987 which discloses a two piece ventilator consisting of a mounting cover frame and a shutter support housing which is frictionally mounted in the crawl space opening.
As mentioned above, passive ventilator systems rely on adequate air pressure or wind in order to be effective. This poses several problems, the first being that a constant source of said pressure is impractical and will rarely occur naturally. Also, many structures with crawl space areas have openings constructed within the surrounding foundation wall that, without the aid of one of those above mentioned ventilators, act as a passive system by themselves, and seemingly eliminate the need to add expensive and redundant additional passive systems.
In conclusion, in order to actively ventilate the air from a crawl space to the outside environment, it becomes obvious that the need to incorporate some sort of powered means to exhaust the air is essential in successfully ventilating such an area. In pointing this out, a number of existing ventilators are found that realize this need and are described as follows.
U.S. Pat. No. 5,294,049 to Timothy J. Trunkle et. al. , Mar. 15, 1994 discloses a temperature responsive louver housing ventilator with a fan controlled by a bi metallic element. This patent is designed to pull air from locations obstructed from direct air flow by incorporating the use of a flexible elongated duct that is mounted to the subfloor joicing along with a flexible adaptor hood to connect the ducting to the ventilator unit. By localizing where the air is drawn from, ventilation becomes limited and installation difficulty is compounded with the use of a duct that must be physically mounted under the subfloor. This ventilator also requires hardwiring and it is frictionally mounted within the crawl space opening.
U.S. Pat. No. 5,253,804 to Paul M. Sarazan et. al., Oct. 19, 1993 also incorporates the use of louvers and a temperature and humidity controlled fan in their ventilator design. This particular ventilator requires the skills of a professional to install in that it must be hard wired to the dwelling""s main power source.
Another patent which uses louvers and temperature and humidity sensors is U.S. Pat. No. 5,881,951 to Peter W. Carpenter, Mar. 16, 1999 which also incorporates the use of a computer device that interprets information from temperature and relative humidity sensors and, in turn, adjusts and controls activation of the fan.
Other inventors have used alternative methods as actuators of their ventilators, such as a photocell, which senses outdoor light changes in connection to activating the ventilator. This component is utilized in U.S. Pat. No. 4,953,450 to Paul D. Remondino, Sep. 4, 1990, which discloses a ventilator that is to operate at a predetermined time interval, after sundown and before dawn. This method limits the time in which the unit is in operation and, does not take advantage of humidity or other environmental factors during the day.
Another ventilator which uses a different approach to activating,the fan is U.S. Pat. No. 4,877,182 to Robert J. Pugh et. al., Oct. 31, 1989 in which is disclosed a two piece ventilator system, having an intake unit and an exhaust unit, which are operated by a solenoid which in turn activates the louvers and fan. In this patent, the exhaust unit incorporates the use of a remote humistat and a fan, and the intake unit utilizes no source for active air flow, such as a fan, but does utilize a temperature sensing device. This poses a problem in that there is only active air flow on the exhaust unit, thus forcing this unit to perform the task of active ventilation on its on. This ventilator is too complex, utilizing a number of elaborate components. Its method of installation and wiring are not described, only the method of operation.
One invention found in the prior art deals specifically with the issue of gases. U.S. Pat. No. 5,131,887 to John E. Traudt, Jul. 21, 1992 discloses an inlet fresh air system which has an adjustable air flow rate and is activated in response to soil gas pressure. It incorporates the use of a ducting system that must be installed under a building""s sub-floor, and uses a blower to move the air. It does not act as a ventilator, but conversely, draws air into the crawl space area.
My own invention seeks to exploit the use of active air flow, by having the ability to use a number of ventilator units, allowing for custom ventilation and to increase the rate of air exchange through the crawl space air, ensuring adequate expulsion of harmful toxins and contaminants. In so far as we are aware, the patent documents identified in the proceeding paragraph, disclose ventilators which are either passive, or require permanent installation in the foundation wall or under the subfloor, or utilize louvers, temperature or humidity sensors and other complex components that increase production costs and risks of mechanical failure.
We have now invented, and disclose herein, a molded plastic crawl space ventilator which is similar to those heretofore proposed, in that it forcibly removes air from beneath a dwelling""s crawl space area and installs into an opening in a foundation wall. Our novel crawl space ventilator varies from those heretofore proposed, in that it is not permanently installed into mortar, and is not permanently attached to the screen in the vent opening or existing passive ventilator covers commonly found in most foundations, be they mortar or brick, finished with stucco, concrete, wood siding, etc. Further, the crawl space ventilator may be made from any convenient moldable, paintable plastic, uses a minimum of materials, is lightweight, and eliminates the need for complex components, such as temperature or humidity sensors, louvers and methods for controlling such louvers. The ventilator of this invention also utilizes pre-existing high efficiency low voltage fan(s), giving it the ability to be connected to standard irrigation or landscape lighting timers, further increasing its convenience and extending the capabilities of such systems.
Objects and Advantages
Objects of the present invention include providing a crawl space ventilator:
Which actively expels air from a crawl space area to the outside environment
Which utilizes a minimum of plastic material
Which reduces installation costs
Which installs non permanently to existing vent screens permitting relocation to alternate openings in the foundation, allowing for custom ventilation depending on individual circumstances
Which can assist heating and air conditioning by drawing in cool night air in summer and warm day air in winter
Which utilizes pre-existing high efficiency, low voltage fan(s)
Which avoids the use of complex components, such as temperature and humidity sensors, louvers, etc.
Which does not require hardwiring, instead relying on low voltage fan(s), thus having the ability to be connected to pre-existing irrigation or landscape lighting timer/transformer, expanding the capability of theses systems by including a ventilation station to their network, and also eliminating the need for additional timer systems.
Which can be directly connected to a standard transformer
Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the drawings, or may be learned from the practice of the invention.